LXR linux/include/crypto/sha256

   1/*
   2 * sha256_base.h - core logic for SHA-256 implementations
   3 *
   4 * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 as
   8 * published by the Free Software Foundation.
   9 */
  10
  11#include <crypto/internal/hash.h>
  12#include <crypto/sha.h>
  13#include <linux/crypto.h>
  14#include <linux/module.h>
  15
  16#include <asm/unaligned.h>
  17
  18typedef void (sha256_block_fn)(struct sha256_state *sst, u8 const *src,
  19                               int blocks);
  20
  21static inline int sha224_base_init(struct shash_desc *desc)
  22{
  23        struct sha256_state *sctx = shash_desc_ctx(desc);
  24
  25        sctx->state[0] = SHA224_H0;
  26        sctx->state[1] = SHA224_H1;
  27        sctx->state[2] = SHA224_H2;
  28        sctx->state[3] = SHA224_H3;
  29        sctx->state[4] = SHA224_H4;
  30        sctx->state[5] = SHA224_H5;
  31        sctx->state[6] = SHA224_H6;
  32        sctx->state[7] = SHA224_H7;
  33        sctx->count = 0;
  34
  35        return 0;
  36}
  37
  38static inline int sha256_base_init(struct shash_desc *desc)
  39{
  40        struct sha256_state *sctx = shash_desc_ctx(desc);
  41
  42        sctx->state[0] = SHA256_H0;
  43        sctx->state[1] = SHA256_H1;
  44        sctx->state[2] = SHA256_H2;
  45        sctx->state[3] = SHA256_H3;
  46        sctx->state[4] = SHA256_H4;
  47        sctx->state[5] = SHA256_H5;
  48        sctx->state[6] = SHA256_H6;
  49        sctx->state[7] = SHA256_H7;
  50        sctx->count = 0;
  51
  52        return 0;
  53}
  54
  55static inline int sha256_base_do_update(struct shash_desc *desc,
  56                                        const u8 *data,
  57                                        unsigned int len,
  58                                        sha256_block_fn *block_fn)
  59{
  60        struct sha256_state *sctx = shash_desc_ctx(desc);
  61        unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
  62
  63        sctx->count += len;
  64
  65        if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) {
  66                int blocks;
  67
  68                if (partial) {
  69                        int p = SHA256_BLOCK_SIZE - partial;
  70
  71                        memcpy(sctx->buf + partial, data, p);
  72                        data += p;
  73                        len -= p;
  74
  75                        block_fn(sctx, sctx->buf, 1);
  76                }
  77
  78                blocks = len / SHA256_BLOCK_SIZE;
  79                len %= SHA256_BLOCK_SIZE;
  80
  81                if (blocks) {
  82                        block_fn(sctx, data, blocks);
  83                        data += blocks * SHA256_BLOCK_SIZE;
  84                }
  85                partial = 0;
  86        }
  87        if (len)
  88                memcpy(sctx->buf + partial, data, len);
  89
  90        return 0;
  91}
  92
  93static inline int sha256_base_do_finalize(struct shash_desc *desc,
  94                                          sha256_block_fn *block_fn)
  95{
  96        const int bit_offset = SHA256_BLOCK_SIZE - sizeof(__be64);
  97        struct sha256_state *sctx = shash_desc_ctx(desc);
  98        __be64 *bits = (__be64 *)(sctx->buf + bit_offset);
  99        unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
 100
 101        sctx->buf[partial++] = 0x80;
 102        if (partial > bit_offset) {
 103                memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);
 104                partial = 0;
 105
 106                block_fn(sctx, sctx->buf, 1);
 107        }
 108
 109        memset(sctx->buf + partial, 0x0, bit_offset - partial);
 110        *bits = cpu_to_be64(sctx->count << 3);
 111        block_fn(sctx, sctx->buf, 1);
 112
 113        return 0;
 114}
 115
 116static inline int sha256_base_finish(struct shash_desc *desc, u8 *out)
 117{
 118        unsigned int digest_size = crypto_shash_digestsize(desc->tfm);
 119        struct sha256_state *sctx = shash_desc_ctx(desc);
 120        __be32 *digest = (__be32 *)out;
 121        int i;
 122
 123        for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be32))
 124                put_unaligned_be32(sctx->state[i], digest++);
 125
 126        *sctx = (struct sha256_state){};
 127        return 0;
 128}
 129